Apologies if this has already been covered but I couldn't see it from skimming the 11 pages or so of this thread so far.
I have a DVC discounted WDW AP. Upon renewal this should renew under the current offer to a 15 month AP.
If I then upgrade it to a Premier Passport, it should have the same expiry date - so I would have a 15 month Premier Passport. Is this correct?
Secondly, I read at the beginning of the thread that to upgrade you pay the difference in price between what you
paid for your existing AP, and the cost of the new Premier Passport. Is it definitely the difference between the price you actually paid, or is it the difference in cost (i.e. the notional price)? I have read that there is no DVC discount on the Premier Passport, but it seems strange that they would effectively clawback the discount DVC members have already received on the purchase of a WDW AP. It would make more sense (not that that's ever meant anything

) if there was no further discount on the $80 or so cost of upgrading from one to the other.
Apologies if this has been covered previously - the search engine isn't the best

- and thanks for your assistance.